A federal grand jury in Houston indicted 27-year-old Conrad Alvin Barrett on Thursday.
Investigators say Barrett slugged the 79-year-old victim, breaking his jaw in two places, in a Nov. 24 attack in Katy. They say he laughed and shouted "knockout" as the man fell to the ground.
Investigators say Barrett videoed the attack on his cellphone and shared the recording.
Barrett was arrested Dec. 26 and remains in custody pending a court hearing next week.
The Associated Press left a message for defense attorney George Parnham seeking comment.
Parnham has said Barrett has a bipolar disorder and was off his medication when the attack happened.